No longer required - We can achieve this from Edit Preferences tab from Workspace settings. Refer to comment from @jeff_bloomer
Description - The custom palette accessible from Project Info & Settings have the ability to be saved and reused for other dashboards easily.
Why is this feature important to you - For each new dashboard that starts afresh, if we need to change the theme, we have to gather the hex color codes or copy from the previous dashboards.
How would you like the feature to work - An option to save custom palette as brand template or any other given name.
Current Behaviour - For each dashboard, we have to add hex codes for customizing the dashboard.